# 75.829 Tramming continuous mining machines in and out of the mine and from section to section.
(a) *Conditions of use.* Tramming the continuous mining machine in and out of the mine and from section to section must be done in accordance with movement requirements of high-voltage power centers and portable transformers (§ 75.812) and as follows:
(1) The power source must not be located in areas where permissible equipment is required;
(2) The continuous mining machine must not be used for mining or cutting purposes, unless a power center is used in accordance with §§ 75.823 through 75.828 and §§ 75.830 through 75.833;
(3) Low-, medium-, and high-voltage cables must comply with §§ 75.600-1, 75.907, and 75.826, as applicable; and
(4) The energized high-voltage cable must be mechanically secured onboard the continuous mining machine. This provision applies only when using the power sources specified in paragraphs (c)(2) and (c)(3) of this section.
(b) *Testing prior to tramming.* Prior to tramming the continuous mining machine,
(1) A qualified person must activate the ground-fault and ground-wire monitor test circuits of the power sources specified in paragraph (c) of this section to assure that the corresponding circuit-interrupting device opens the circuit. Corrective actions and recordkeeping resulting from these tests must be in accordance with §§ 75.832(f) and (g).
(2) Where applicable, a person designated by the mine operator must activate the test circuit for the grounded-phase detection circuit on the continuous mining machine to assure that the detection circuit is functioning properly. Corrective actions resulting from this test must be in accordance with § 75.832(f).
(c) *Power sources.* In addition to the power center specified in § 75.825, the following power sources may be used to tram the continuous mining machine.
(1) *Medium-voltage power source.* A medium-voltage power source is a source that supplies 995 volts through a trailing cable (See Figure 1 of this section) to the continuous mining machine. The medium-voltage power source must—
(i) Not be used to back-feed the high-voltage circuits of the continuous mining machine; and
(ii) Meet all applicable requirements for medium-voltage circuits in 30 CFR 75.
(2) *Step-up transformer.* A step-up transformer is a transformer that steps up the low or medium voltage to high voltage (See Figure 2 in this section) and must meet the following requirements:
(i) The trailing cable supplying low or medium voltage to the step-up transformer must meet the applicable requirements of 30 CFR part 75;
(ii) The high-voltage circuit output of the step-up transformer supplying power to the continuous mining machine must meet the applicable provisions of § 75.824;
(iii) The step-up transformer enclosure must be—
(A) Securely mounted to minimize vibration on:
(*1*) The continuous mining machine; or
(*2*) A sled/cart that must be connected to the continuous mining machine by a tow-bar and be in close proximity to the mining machine.
(B) Grounded as follows:
(*1*) Connected to the incoming ground conductor of the low- or medium-voltage trailing cable;
(*2*) Bonded by a No. 1/0 A.W.G. or larger external grounding conductor to the continuous mining machine frame; and
(*3*) Bonded by a No. 1/0 A.W.G. or larger external grounding conductor to the metallic shell of each cable coupler.
(C) Equipped with:
(*1*) At least two interlock switches for each of the enclosure covers; and
(*2*) An external emergency stop switch to remove input power to the step-up transformer.
[75 FR 17549, Apr. 6, 2010]